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Case Study: Ceniceros WholeHouse Performance RetrofitBruce CenicerosHome Owner
The home Built: 19982 stories2850 ft2Slab on grade30% moreefficient thanTitle 24 (SMUDAdvantageHome)
The Problem(How New Homes are Built) 3-6 standard floor plans per subdivision Mass-production techniques Contractors hired by low-bid, incentive is to do asmany homes in a day and pass inspection Insulating contractors may insulate 2-3 homes in asingle day! Plumbers and electricians may punch holes or moveinsulation without understanding impact on energyperformance Energy and comfort performance suffers
Our Motivations Buying a house: 2,800 ft2 tract home inFolsom, CA built in 1998 Were aware of common home performanceproblems (uneven temperatures, moisture,poor IAQ, high energy costs) Wanted to identify extent of problems toinform purchase decision and allow financingof comfort improvements in mortgage
Flow hoodmeasures airflow fromeach register
Infrared camera spotsthermal bypasses(Blue or black areas)
Knee wallwas poorlyinsulated(gaps,sagging)
Knee wallwas notinsulated
What the Contractor Found Upstairs was 70 F hotter than downstairs in heatingmode IR camera revealed poorly insulated knee-walls andnumerous other thermal bypasses Duct leakage 7% Envelope leakage 1,900 cfm50 Insufficient airflow Well-sized but inefficient AC Over-sized and inefficient furnace Ventilation fans used too seldom due to noise Furnace fan very loud and draws 1,060 Watts 13 out of 37 low-e windows were installed backwards
ImprovementsTo Improve Comfort: Repair thermal bypasses Insulate knee-walls properly Insulate floor assembly between garage and upstairsbedroom Seal envelope to achieve minimum desired naturalair changes (to 1200 cfm50) Seal ducts to less than 3% leakage Install additional return in master bedroom Install balancing dampers and perform air balance
ImprovementsTo Improve Comfort: Reconfigure ducts to allow burying in insulation Install engineered and re-sized return grills to achievebetter mixing and reduce noise Provide return air paths from bedrooms Install knee wall dams and re-insulate attic to R-38 Right-size AC and furnace Perform test-out to confirm performance (includingcombustion appliance safety testing)
ImprovementsTo reduce energy costs further: Freus 17 EER evaporatively-cooled condensor 95% furnace with high efficiency variable speed fan NightBreeze night ventilation system Install fluorescent lighting throughout home In-home energy monitor
Performance Contract Guaranteed that performance targets will be hit:––––Less than 3% duct leakageLess than 1200 cfm envelope infiltrationProper air flow to all rooms and across coilLess than 3 degree temperature differential between allrooms and floors in the house– Quiet noise levels (NC 25-30)– At least a 56% reduction in heating and cooling costs Total Installed Cost including Lighting and controls: 21,400
Would Any Normal Family Pay 21,000for Better “Home Performance”?Our reasons to want a healthy, comfortable house:How much does a kitchen remodel cost?Which is more important, a stylish kitchen or a comfortableand healthy indoor living environment?(and the kitchen remodel doesn’t pay for itself)
Fixing the constructionFlaws
Installing a new“right-sized”evaporator coiland furnace
Checking therefrigerant charge ofthe high efficiencyevaporatively-cooledair conditioner
Re-insulating andsealing the knee walls
A sealed walltop plate
Large gaps werepresent where stairsabutted the walls
A “smoke” stick is used tolocate leaks, in this casebetween the floor assemblyabove the garage into house
Engineered supply grilles resized forproper velocity and throw at design air flow
And we kept going
In-home energy display
Control of “Vampire” Loads Smart Strips forcomputerperipherals &home theatercomponents Dedicatedcharging station
Energy Star Appliances and fans Front loading washerand fridge among topten most efficientmodels High Efficiency ceilingfans with temperaturebased controls
CFLs in every fixture but theoven
LED down lights inhome office (dimmable!)
Lighting and fan Controls Timers Occupancy Sensors Temperature-basedceiling fan controls
Smart Kitchen Remodel Good lighting designLED down lightsLED undercabinet lightsFluorescent cove lightsMulti-switchingHigh-efficiency right-sizedexhaust fan Charging station Recycling, compost bins
Behavior Close shutters on sunnyside in summer Optimal use of setbackthermostat Turn off when room isvacant Use ceiling fans Watch energy monitor,be aware of big loads,and act when unusualthings happen
Results of Our HomePerformance Retrofit
Natural Gas Savings160Total therm savings: 44%140Heating therm savings: rms100
Electric Savings1,800Total kWh savings since retrofit: 64%*1,600Air Conditioning kWh savings: 81%*1,400*Despite 10-20% energy penalty of pre-cooling testing insummer of 2007—future savings will be greater.Before(4 yr rOctoberNovemDe be rcemberJanuaryFebruaryMarch-SeptemkWh1,200
Average Monthly EnergyCosts: 85Total Bill Savings:52% 1,400/year
The Confidence that our Home isComfortable and Healthy:PRICELESS Two months after the retrofit was complete, KiraSabrina was born via a planned home birth
Results of Home PerformanceRetrofitMost importantly, achieved all comfortperformance targets: Upstairs and downstairs are now the sametemperature All rooms are comfortable No longer can feel or hear the HVAC system Musty smell in under-stair closet gone Peace of mind that indoor environment ishealthy
Next, Heat pump water heater 85% of operating cost of a 94% efficientcondensing gas WH Demand response capable Larger storage more peak shifting capabilityand excess generation storage Zero carbon when powered by PV
Now, time for PV!
Now, time for PV!
What homeowner’s want It all comes down to value Bill savings was least important motivator Priorities:––––Healthy living environmentComfortAesthetics (look, noise reduction)Helping improve the environment
What homeowner’s want Clean, trustworthy, prompt contractors who dowhat they say the will do. Simple choices, customized packages Minimize hassle factor
Saving energy can becomeaddictive A utility can build deeper engagement over timeand change a customer’s values One small action leads to another, then another Timing is everything. Know key triggers, haveresources in place, and engage customer at theright time. People care about what their peers do People are competitive by nature
Pathway todeeperengagementUtility benefits: Deeper customerengagement High customersatisfaction Loyalty Customer retention Reduced infrastructurecosts44ComfortSafe environmentLow billsFunStatusEVSolarTOU ratesCarbon offsetsGreenergyDR thermostatWhole house retroHome assessmenEnergy Star fridgeSmart pwr stripsCFLs
air changes (to 1200 cfm 50) . Freus 17 EER evaporatively-cooled condensor 95% furnace with high efficiency variable speed fan . air conditioner . Re-insulating and sealing the knee walls . A sealed wall top plate .
